New Vessel Fuel Efficient Design and

Construction Considerations

Medium and Long-Term Options

By

Dag Friis

Christian Knapp

Bob McGrath

Ocean Engineering Research Centre

MUN Engineering

Overview : Introduction

Design Cycle Statement of Requirements Design Operational Considerations

Vessel Design Considerations Base Efficiency Considerations in Design Ongoing Simulations & Testing What to Look for going forward

Conclusions

Introduction: The changes in the fishery since the moratorium in ’92

have significantly changed the demands on fishing vessels and crew

One has a need for the ability to fish multiple species & Areas This has put undue pressure on vessel design without a

corresponding change in vessel size restrictions Harvesters are Steaming farther from Shore and thus subject to

significantly increased sea states The time for Steaming to and from grounds has increased

This means that there is a need for Naval Architectural & Engineering expertise in order to ensure that Vessels are designed to be: Safe, stable and economically advantageous platforms for

executing the fishery of today and the future

This should lead to a return to more reasonable & proportional vessel dimensions.

Statement of Requirements

This is what the Naval Architect/Designer uses as a framework for the design of your boat

It should state the performance objectives that the design should achieve in order to make the boat a viable business proposition as well as a safe workplace for you and your crew

Preliminary Economic Considerations

Basic Design CycleStatement of Requirements:

Hold Space – Quota Requirements

Principal Dimensions (Parametric Study)

Expected Lifetime

Operational Considerations

Preliminary Design Calculations

• Resistance

• Powering

• Weight Estimate

• Propellers

General Arrangement

• Preliminary Shape

• Outfit

• Auxiliary Power

• Gear

Cost Estimate

• Economic Analysis

• Life Cycle

• Payback Period/Rates of Return

Performance Predictions

• Seakeeping

• Seaway Powering

• Simulations/Modelling/Tank Testing

• Noise/Vibration Issues

• Fish & Crew Disruption

WEATHER CONSIDERATIONS:NEWFOUNDLAND AND LABRADOR HAS A

LARGE AND DIVERSE COASTLINE WITH

SIGNIFICANT VARIATION IN OFFSHORE

CONDITIONS:

1. Where do you fish

2. What do you fish

3. What Gear is Required

4. How long do you intend to keep fishing

Overview of Considerations: Vessel Handling and other characteristics Directional Stability Noise and Vibration Considerations Moment induced Interrupts (MII’s)

Fish Harvesting is a business Efficiency in harvesting Energy Efficiency Decisions Based on Return on Investment

Catch handling/stowage methods, for example: On Deck Chill Tank Boxing (with desired capacity) RSW (with desired capacity)

DFO vessel size restriction applicable criterion

8

Design Considerations:

**THE LARGER THE WAVE SYSTEMS AND

THE MORE WATER PULLED IN THE WAKE

THE MORE FUEL SEND UP THE STACK FOR

LITTLE INCREASE IN PERFORMANCE**

EFFECT OF BOW TYPE ON RESULTANT WAVE SYSTEM

Standard Bow ~ 15 Knots Full Scale Equivalent (L/B = 3)

Bulb A ~15 Knots Full Scale Equivalent (L/B = 3)

Case Studies: 34’11”, 44’11”, 64’11”Energy Efficiency Simulation:

Vessel Information:

65 Footer

L/B = 2.82245 Footer

L/B = 2.02835 Footer

L/B = 2.26

Overall Vessel length 64'11" 44'11" 34'11"

Design Water Line Length 63'6" 42‘7" 33'11"

Design Displacement Cu. #: 17536 32.80 LT ?

Design Draught 11' 2.27 M 4'

Beam at Design Draught 22'6" 21' 15'

Depth to keel 12' 9' ?

1/2 Angle of Entry of Bow ? ? 40 degrees

Engine Power 720 HP 440 HP 250 HP

Gearing Ratio 5.07:1 (5;1) 3.00:1 2.79:1

Propeller type Hawbolt 4 Wing 3 Wing Brass Fixed 25" x 27"

Propeller Diameter 66" 44" 25"

Pitch 52 ? 27"

Blade Area Ratio 76" (5" Clearance) ? ?

Operating RPM: Steaming 1500 RPM 1400-1450 RPM 1600 RPM

Operating RPM: Fishing/Towing

1250 RPM (Max.

1800) 600-700 RPM

800 RPM

(Max. 2600)

Controllable Pitch prop? N/A N/A N/A

11

Case Studies: Simulations & Analysis Appendage Drag: Best and Worst Case

Hull Surface Fouling: Drag Clean vs. Fouled

Effect of ½ Angle of Entry : varied from 110% of As-Built to 70% As-Built Change in Displacement with bow ½ Angle

All other parameters constant

Effect of Immersed Transom: Varied as 100% of Midship Draught to 10% of Midship Draught (A box to a Wedge!) Change in Displacement with transom draught

All other Parameters Constant

Estimated Power Requirements in a Seaway: Calm to SS6

Estimated Powerw in a Seaway for Ideal Hull:

10% of Midship Draught Transom Immersion

70% of As-Built ½ Angle

Overall increase in length by 5 ft or 10ft for the 65’

Lengthened Skeg to achieve greater propeller clearance

Change in Displacement with length increase

Propeller Simulations: (Overall Propulsive & Required Engine RPM & Power)

As-Built Efficiency

Optimised Propeller, As-Built Hull, Efficiency:

Idealised Hull and Propeller

12

•Generate Test Series & Design Envelope

•Three bulbous bows designed & Tested in:Seakeeping (Zero speed)

Resistance

Self-Propulsion

•Vessel Lengths Tested to date:45’

65’

110’

100

90’

Powering Breakdown 35’:

-40.00%

-20.00%

0.00%

20.00%

40.00%

60.00%

80.00%

2 3 4 5 6 7 8

Pe

rce

nta

ge

Dif

fere

nce

[%

]

Speed [knts]

Estimated Effect of Hull Fouling, Appendage , Immersed Transom and Half Angle on Service Power with As Built (L/B ~ 2.33)

Appendage Drag

Fouling Drag

33% Increase in Transom Draught

66.7% Increase in Transom Draught

100% Increase in Transom Draught

33% Reduction in Transom Draught

66.7% Reduction in Transom Draught

10% Increase in Half Angle

10% Reduction in Half Angle

Simulated ‘Idealised’ Vessel:

Lengthened Bow – Finer & Gradual Shape

Reduced Shoulder - Reduced Flow Separation

Lengthened Bow – Finer & Gradual Shape

15

Considerations of Energy Efficiency In Hull Form Design :

Low L/B ratios

Requires large amount of energy to accelerate water out and around the hull

High likelihood of flow separation in the aft body and resulting energy absorbed in eddy making

Blunt Bow – Large Angle of Entrance

High pressure over a large area at the bow creating large bow wave

Possibly creating a second bow wave system at the shoulder

EFFECT OF BOW & L/B RATIO ON RESULTANT WAVE SYSTEM L/B = 4.074 (Bulb A) L/B =2.407 (Standard Bow)

L/B 2.4

17

The Influence of Vessel Length on Seakeeping:

• Investigated Seakeepingperformance and Influence on the number of days available for fishing.

• Seakeeping done on all bows for 90’ at ahead, ahead quartering, beam and stern seas.

• One Test Included a basically modelled anti-roll tankVessel

Length

Critical Wave

Height

Threshold,

MII/minute

65 feet 3.0 m 0.955

85 feet 3.75 m 1.06

90 feet 4.0 m 0.992

110 feet 4.25 m 0.856

150 feet 5.0 m 1.08

Critical Wave Height

y = -0.0002x2 + 0.059x - 0.0718

R2 = 0.983

0

1

2

3

4

5

6

0 20 40 60 80 100 120 140 160

Vessel length in feet

Cri

tical W

ave H

eig

ht

in m

etr

es

Critical Wave Height (m)

Poly. (Critical Wave Height

(m))

The influence of Vessel Length on Fuel Consumption:

Investigated Energy Efficiency as a function of vessel length

Estimated the Fuel Consumption per Pound of Catch over a variety of Lengths

% fuel rate per lb

0.00%

20.00%

40.00%

60.00%

80.00%

100.00%

120.00%

0 20 40 60 80 100 120 140 160

Vessel length in ft

fue

l c

on

su

mp

tio

n r

ate

re

lati

ve

to

65

' v

es

se

l

% fuel rate per lb

Influence of Vessel Beam on Fuel Consumption:

10 knots

Pservice

Difference

B/L Beam (ft) Pservice (kW) % Relative to 27'

0.278 25 486.46 -9.02%

0.300 27 534.68 0.00%

0.311 28 557.52 4.27%

0.322 29 581.41 8.74%

0.333 30 605.79 13.30%

0.356 32 654.43 22.40%

0.378 34 702.95 31.47%

0.400 36 752.50 40.74%

0.422 38 802.34 50.06%

0.444 40 852.87 59.51%

Difference

Relative to 27’

B/L Beam L/24hrs litres/24hrs

0.278 25 600.00 -48.0000

0.300 27 648.00 0.0000

0.311 28 672.00 24.0000

0.322 29 696.00 48.0000

0.333 30 720.00 72.0000

0.356 32 768.00 120.0000

0.378 34 816.00 168.0000

0.400 36 864.00 216.0000

0.422 38 912.00 264.0000

0.444 40 960.00 312.0000

20

The Effect of Stern Shape and Immersed Transom on Design:

Submerged Transom Creates a very low pressure at the stern resulting in

a large mass of water being dragged along with the boat

Poor flow of water to the propeller Resulting from flow separation due to the high rate

of change in stern lines

Further aggravated by the presence of a large amount of submerged transom area

Stern Rise = Low Transom immersion

High Prop Clearance

NO Stern Rise = High

Transom immersion =

Inefficient

Overview of Considerations:

0

50

100

150

200

250

300

350

400

450

0 1 2 3 4 5 6 7 8 9

Se

rvic

e P

ow

er

[kW

]

Speed [knts]

Comparison of Estimated Service Power in a Seaway for an As-Built 35' (L/B = 2.33) with an Optimised & Lengthened 39‘11”

Version (L/B = 2.66)

As-Built Calm

As-Built ss4

As-Built ss5

Modified Calm

Modified ss4

Modified ss5

Overview of Considerations:

0

500

1000

1500

2000

2500

3000

3500

4000

4500

1 3 5 7 9 11 13

Se

rvic

e P

ow

er

[kW

]

Speed [knts]

Comparison of Estimated Service Power Required in a Seaway for an As-Built 65' (L/B = 2.89) with an Optimised & Lengthened

74‘11” Version (L/B = 3.33)

As-Built Calm

As-Built ss4

As-Built ss5

As-Built SS6

Modified Calm

Modified ss4

Modified ss5

Modified ss6

Potential Design Aids/Tools: Tank Testing & Simulation:

Design Predictions – What it Can Do:

Tank Testing, Simulations & Data Analysis :

• Performance & Powering

• Propeller, Gearing and Powering Design Envelopes

• Dynamic Stability

• Induced Motions/Seaworthiness

• Effects of Appendages and Bulbous bows

• Effect of Roll Dampening Devices

Testing Example: Effect Of Speed On Wave System & Powering

Standard Bow~ 8.5 Knots Full Scale Equivalent (L/B = 2.407)

Standard Bow~ 10.5 Knots Full Scale Equivalent (L/B = 2.407)

VIDEO 8.5 VIDEO 10.5

Design Tools: FUEL RATE COMPARISON:

0

500

1000

1500

2000

2500

3000

3500

4000

0 500 1000 1500 2000 2500 3000

To

tal

Fu

el

Co

nsu

me

d [

l]

Engine RPM

Fuel Consumption Over 100 Nautical Miles with Hull and Prop Variation (Maximum RPM ~ 12 Knots Speed)

As Built Prop

Optimised Prop

Ideal Hull Prop

EX :Reasonable Vessel Parameters 75’ x 22’:Fewer Decks – Less Windage & Iceing Surface

~ Lower Centre of Gravity

Material Considerations: Fibreglass:

Weight Savings

Moulded Design Facilitates:

Clean, Fair Surface Finish

Great variation in Possible Geometric Shapes

Chemically Inert (doesn’t rust!)

Potential Cost savings for smaller vessels and series builds

Caution: Cost of Resins can vary with cost of Fuel

Can have water ingress and de-lamination/blistering issues

Steel: Strong and Durable (Large margin of safety especially against impact)

Easier to repair large structural damage

Can build Any size, not mould dependent

Chemically Sensitive Corrosion

Higher maintenance costs

It may challenge some of our pre-conceptions of how an efficient, safe, reliable and economically viable vessel looks:

Expect:

Research of Alternative Equipment, Materials, Fuel Systems and Machinery and Associated Economic Costs& Payback Periods

Clear Documentation on Vessel Trim and Stability (DFO & Transport Canada Requirements/Regulations)

Comprehensive Design Drawings and Documentation

Vessel Incline Tests

Sea Trials

Documentation of As-Built Vessel Performance

What Proper Vessel Design Can Provide:

Proportional Vessel Parameters (Closer to our Ideal):

•High L/B Ratio

•Gradual Changes

in Hull Shape

•Fine Bow = Low

Half Angle of

Entrance

•Stern Rise

•Needs to be

Cleaned and Faired

•Length to Beam is very significant (Higher L/B more efficient)

•Increased Length overall is more efficient

•Lowest Transom Immersion as possible

•Smallest Bow Half Angle Possible without creating an unnecessary abrupt change at the Shoulder

•Stern tube and Submerged Stern Shape should maximise space for Propeller (ensuring min. Clearance) & Ensure Clean Flow

•Propellers should be optimised for cruising (in most cases) in at the most efficient speed and engine RPM while ensuring sufficient Bollard Pull

•Lower Superstructure for reduced Windage and Iceing Areas

•Fewer Above water Decks = lower centre of gravity (NO NEED for permanent Ballast in proper design only Ballast Tanks )

•CPP, different Nozzles, alternate Rudders, etc. Should be considered

•Properly Designed Bulbs are very useful at minimising required Power (and hence RPM) at Intended Design speed

•Properly Designed bulbs reduce motions in a seaway

•Properly Designed and Tuned Anti-Roll tanks are the most cost effective at reducing roll motions in a range of sea states

•Fuel Efficient Engines and Monitoring Systems

•Modular Gear Installation for Easy conversion to different Species

•Material Selection: Fibreglass vs. Steel

•AS GRADUAL CHANGES IN HULL SHAPE AS POSSIBLE! Fine Bow and Faired, Rising Stern!

CONCLUDING SLIDE